Testors/McCoy .049 smoked...

Ken Cook wrote:                     That's the best thing that could've happened to that engine. However, it should be framed as it does indicate it did run.

That's cold Ken ..........

chevyiron420 wrote:Your piston and cylinder from the pipe bomb will fit perfectly on your mccoy. The problem is the crank. They will break cranks right through the hole that line up with the carb. Once I settled on the cox 6x3 props and fuel with 25% oil, I had no more crank failures. Your crank may have been broken forcing a stuck piston. I have been using these engines for a very long time and I like them. The crank from a wen mac will work fine. It wont be counter weighted but it works. Only the later mccoys were counter weighted.
Phil

Thanks for the info Phil. Do you suppose that these engines come close to their rated design-rpm (red-lining) when running the smaller Testors propellers along with using an improper fuel in them?

I have an ancient un-opened quart of Testors/McCoy glow fuel.. and have to wonder what the formula is.. or was.




I've never run a Testors .049 of any type.. and was hoping to run this one. At least this type can be easily mounted to an airplane. I'll keep an eye out for some parts-engines.

Oldenginerod wrote:

I eBay purchased a heap of parts a while ago that were advertised as to suit OK Cub, but I could tell from the picture they weren't.  Turns out they were Wen Mac/Testors/McCoy.  There would have been more than 20 piston/rod assemblies which all looked brand new.  I've used these to repair several of these engines, but I needed to check carefully when chosing as there was a huge variation in the ball socket clearance.  I just went through and chose the tightest ones for my rebuilds, which actually makes a significant difference to the running of the engine.  Sadly these are not swaged in like a Cox so you cannot take up the clearance.  What ya get is what ya got.

Roddie, if that Testors fuel doesn't specify that it's suitable to .049s then I'd be careful.  For one thing, the nitro content could be as low as 5%-10%.  The Testors .049 won't handle low nitro as well as Cox.  There's a fair chance the oil content will be fine as it was probably formulated with plain bearings and iron pistons in mind.

No reason why you can't just use your 25%-35% Cox fuel, but I'd be sticking to the lower nitro end of the scale to preserve the bottom end, and those hard to find heads.

A little more discovery with my broken engine. Con-rod to piston fit is VERY loose.. (probably as much as 1mm or .040")    I'm thinking that this loose of a fit may have pounded the bottom-end to the point of failure.

I removed the cylinder and head to find "two" gaskets were installed.



I wanted to see "how stuck" the piston was.. so I opened my bench-vise jaws enough for the rod to drop-in, and tapped very lightly on the top of the piston using a hardwood dowel and tack-hammer. The piston slipped down in the bore quite easily.



It's kind of a shame regarding the ball/socket joint design. It seems to me that a piece of thick-wall steel tube having an inside bevel of a given angle to fit over the outer "cup" of the socket might work as the Cox reset-tool does. It wouldn't be difficult to machine with a lathe. The outer cup of the socket is approx. .250" or 6.35mm. therefor; the tube-tools' ID would need to be smaller than that.. but have a wall-thickness enough for machining a bevel. A couple of light taps with a small hammer would reveal whether the tool would pinch the outer-cup closed enough to take-up the slack in the joint. Unlike the Cox reset tool; the con-rod would merely fit inside the tube.. rather than a slot. Furthermore.. a beveled seamless (and slot-less) tube would be self-centering. Nothing ventured.. nothing gained..  

EDIT: forgot to mention.. the Testors/McCoy fuel can states on the back panel (see directions for use)  "Approved for use with Testors/McCoy model engines, planes and cars". This was the fuel that was sold in department stores that also sold the Testors toys/models. My can has a K-Mart sticker on it. Note also the "Copyright 1970" printed on the very bottom of the can.

Thanks again Rod, I'm sure that some parts will come around locally. Thanks for explaining about the Testors piston/rod construction/metallurgy. Maybe the rod-fit in my engine was poor to begin with.. or maybe whoever had the engine before me, ran it on the wrong fuel?

I wonder if Testors ever tried to reproduce Cox's ball-socket design and got into trouble with patent infringement? That's what happened to Cox, when they tried copy Testors starter-spring design.. or so I've heard.

rsv1cox wrote:roddie, I know of few others that get the pure joy out of investigating the inner workings of these little engines than you do and sharing your findings on these pages.  

My heart did a little flutter when I saw the first picture in this thread of that little pot-bellied McCoy, just the way I used to love receiving them.  Dusty, dirty and containing secrets.  To bad that one has a nasty problem.

I have a few, but none exactly like the one shown. I have several (pictured) that I use for display but I have some incomplete McCoys that I would be happy to send you, a couple with intact crank-shafts that might fit yours.  I'm a little closer geographically than Rod.  

Just PM me your address and they will be on their way.



Bob

Bob.. I'm not sure what drives me in this hobby.. maybe it's just my appreciation for a time where amusements were more than pushing buttons and escaping into a world of social isolation.

I was an under-privileged kid.. and made a lot of my "toys" myself in my early-years. My dad didn't have a job that paid enough to support us.. so my mom sewed "draperies" at home with a rugged-old "Singer" sewing-machine.. (she still uses it..) The Mill-store would deliver bolts of fabric/lining, hooks and patterns for the drapes.. and my mom would cut and sew them together. Heavy brown paper was also supplied for wrapping-up the drapes with string to be picked-up. My mom would frequently cut a 60" x 60" square of paper for me to draw "roads" on with crayons.. for my Matchbox cars. This provided endless hours of fun.

My dad built and flew C/L models from the late 50's thru the early 70's.. along with my uncle and grandfather, when C/L flying was in its prime. I was a "toddler"... and vividly remember those days.. but they were short-lived. Sometime in the early 70's.. the C/L activities diminished.. and my dad lost interest in the hobby and got involved with Barbershop quartet/chorus singing.. which consumed a great deal of his time. I was left to my own devices.. and had two baby brothers by then. It would be 25 some odd years later when I was married; that my dad would show-up at my house with a Cox PT-19 flight-trainer and starting-kit. We both flew it that afternoon.. and that event is what jump-started me into this hobby. My dad actually regained interest and bought a C/L balsa kit and engine. It was the Sterling Mono-coupe and an OS .25FP-S. He never flew it though. He was a "builder" more than a flier. That airplane ended-up with my brother.. received a little "hangar-rash".. and now I have it.



This Veco "Warrior" that he built around 1968 is also hanging in my basement.. It has a Veco .35C engine.



You could say that I'm stuck in a nostalgic vintage C/L modeling time-warp... and that would be fairly accurate.

Here's a photo of the reverse-side of the case.. if that helps.. "THANKS fellas"!